[singularity2001]

If it turns out to be true, it would open the door a bit for connecting Indo-European languages with Semitic languages. In the beginning of the last century it was believed that these were related. Later this came out of vogue. How could they have been so wrong initially? Because both languages families were entangled, as now there is genetic evidence that both languages spread from very close to the Caucasus. It's probably old news for most but in the last 15 years it became clear that Europe was completely resettled, once by Anatolians and then partly by Indo-Europeans. The language of the Anatolians is still unknown.

[mcswell]

"How could they have been so wrong initially?" For the same reason that many other proposed reconstructions were (and some still are) so wrong. Chance matches, sometimes actual loanwords, and bias on the part of some people.